The complete collection of Gunsmoke...
The complete collection of Gunsmoke, 480 shows with 2 auditions shows (June 11, 1949 and July 13, 1949), a 5-hour tribute, and a copy of the pilot television episode (with an opening by John Wayne) is available in Inernet Archive at:
This collection includes all but six episodes which are not known to exist). The shows are on 11 zipped files that can be downloaded and opened. Note that the first CD contains bonus materials, including the Tribute Show, the first TV episode, all known Australian episodes (the Australian series began in 1955; it's not known how many shows aired or how long the series ran), and other material; some people downloading the shows have complained they didn't know the first CD contained material other than the U.S. old time radio episodes (they could have read the description or simply accepted that there was other material and gone on to download the next disk instead of complaining for all the work that others did).